Development in the strobilate phase of Hymenolepis diminuta and many other cyclophyllidean cestodes is extremely rapid. Control of development in these animals will be studied, particularly the roles of nutritional status of the host, worm secretions, and carbohydrate metabolism in the worm. Previous work has indicated that each of these major factors is or may be important in worm development. In the coming year of the project, developmental aspects of hexose transport, effects of protein deficiency and concurrent nematode infection, and inhibition of DNA synthesis by excretory products will be studied. The third of the foregoing is related to the operational mechanism of the "crowding effect" in cestodes in that substances secreted or excreted by the worms can affect the development of other worms in the infection. BIBLIOGRAPHIC REFERENCES: Surgan, M.H., and L.S., Roberts. 1976. Adsorption of bile salts by the cestodes, Hymenolepis dimuta and Hymenolepis microstoma. J. Parasitol. (in press). Surgan, M.H., and L.S. Roberts. 1976. Effect of bile salts on the absorption of glucose and oleic acid by the cestodes, Hymenolepis diminuta and Hymenolepis microstoma. J. Parasitol. (in press).